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Concrete DIY Line Arrays and Subs

LTig

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#6
Some pictures of some concrete line arrays and concrete subwoofers I built

kinda dove into it with a wish and a prayer but the resulting performance is astounding.
Anyway they are a novelty and might be of some interest.
Very nice. What kind of tweeters did you use?
 

bigjacko

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#7
Haha, that's crazy amount of material to cut for the mold. Have you made one using mdf or plywood and compare to this one?
 
OP
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Thread Starter #12
Haha, that's crazy amount of material to cut for the mold. Have you made one using mdf or plywood and compare to this one?
No but.......the original line array with the ribbons was with MDF cabinets from Newform Research. I wanted a semi elipse x-section, concrete is very easy to shape with a mold And dead quite for resonance. The concrete is post tensioned with 7 rods that run their length keeping the entire structure in permanent compression so they will never crack. The front outer baffle is 6061 aluminum 1/2” thick. They weigh 660 lb each and have very bad WAF but are perfect for my man cave. I cross the ribbons at 1K with a 1st order and the mid/bass at 1200 with 2nd order all passive. The plan is to get another amp and go all digital but I have not been overly excited to try this mainly because of the requirements to go to a multi channel DAC.......frankly, they sound so darn good that you question sanity on spending more money to try and make them questionably “better”. Then again as my member name suggests I am “afflicted”. Cheers
 

Harmonie

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#14
Amazing !
The finish is beautiful, can't guess from your first post that it's concrete.

Now more concretely:
Did you reinforce the concrete ?

1609336717019.png


Or, like your sub's picture, did you leave the metal? rods inside ?

Why not fiber/fabric reinforcements ?

This thread may open future opportunities ...
 
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#16
Very clean, ingenious idea to use concrete for the curved enclosure.

I love the subwoofers too, if I'm seeing correctly in those build pictures they are dual opposed drivers? Was the use of the metal plates for baffle and bottom plate something you decided right away, or did you try fully concrete construction and encountered problems?
 
OP
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Thread Starter #17
Amazing !
The finish is beautiful, can't guess from your first post that it's concrete.

Now more concretely:
Did you reinforce the concrete ?

View attachment 102407

Or, like your sub's picture, did you leave the metal? rods inside ?

Why not fiber/fabric reinforcements ?

This thread may open future opportunities ...
there are 1/2” sch 80 pipe running full length with 1/2” threaded rod inside fo both reinforcement but most importantly post tensioning ....as described in previous comment above
 

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Thread Starter #18
Very clean, ingenious idea to use concrete for the curved enclosure.

I love the subwoofers too, if I'm seeing correctly in those build pictures they are dual opposed drivers? Was the use of the metal plates for baffle and bottom plate something you decided right away, or did you try fully concrete construction and encountered problems?
No, they are not opposed they are single 15” massive Peerless STW-350F-188PR01-04 with dual 7.4” voice coils. the rear hole is later covered with a round steel plate c/w concrete plug using four bolts. The front baffle was steel so it could support the heavy driver and allow each of the 8 hex head fasteners to be directly tapped and threaded.
 
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